Thursday, March 08, 2007

Home field advantage and testosterone

In a previous post on home field advantage (HFA), commenter Nate suggested that evolution might have created an innate increase in human performance when defending their own turf. He mentioned a study where British soccer players had higher testosterone when playing at home.

In a separate study published this past summer, a Ph.D. candidate in Canada took saliva samples from 14 players on a minor-league hockey team before and after games. The key finding: Levels of testosterone, which have been found to facilitate assertive and aggressive behavior, were 25% to 30% higher before home games, suggesting the home arena triggered players' elemental instinct to protect their territory. "It has the potential to go a long way in developing techniques to create the ideal physiological profile prior to playing," says Justin Carre, the doctoral candidate at Brock University in St. Catharines, Ontario, who co-authored the study.

7 Comments:

I must be missing something: if there is indeed increased levels of testosterone, and this leads to increased aggressiveness (I am skeptical here) -- that still does not show a link to home team advantage, because no one has shown that aggression leads to an increase in performance. I can think of many instances in virtually all sports where aggression is sub-optimal: the defensive end getting too far downfield to stop the run or the screen, the batter chasing pitches in the dirt, the shooter forcing up shots in the face of double- or triple-teams when his teammates are open...

Agreed. The interesting thing here, I think, isn't any supposed link between aggressiveness and perfromance, but the fact that athlete's bodies react differently at home than on the road. If agressiveness can increase involuntarily, why not speed, or concentration?

I believe it does. I can not recall the study, but it was based on women's soccer teams. They too had an increase in testosterone prior to matches. I do not recall if it was due to general competition or home field advantage. Although from an evolutionary stand point, the behavior would be in line with the same principle as it has been well documented women are just as protective if not more of the "home land" as men.

I am skeptical about this supposed link between increased testosterone and aggression. There is a huge literature on the subject, and I am certainly not an expert, but the field has a history of extrapolating from nonhuman behaviours inappropriately. This is not the best place to discuss this issue, but suffice it to say that what ethologists call "aggression" in nonhuman animals is not necessarily the same thing as "aggression" in humans, and that in turn is not necessarily the same thing as "aggression" on the playing field. This study may have shown a link between home field and testosterone, but not between home field and "aggression", much less aggression in the context of sport, which is an entirely different thing than aggression in an alley fight or aggression on the battlefield.

Fair enough; this is not my area of expertise. I could rephrase my point as:

If there is at least one involuntary biological (chemical) difference in humans at home verus on the road, this suggests there might be others. And this one, or others, might be responsible for at least some aspects of HFA.

Thanks to our friends at google, I tracked down the researcher in the British soccer study I mentioned a while back. He is Nick Neave at the University of Northumbria in England. Here is transcript from an Australian radio show (of all things) interviewing him: http://www.abc.net.au/rn/talks/8.30/sportsf/stories/s566884.htm

Regarding the ongoing discussion here: Ed, I understand your skepticism, but it seems that there are a few high-profile baseball players who believe there is a link between testosterone and performance. Sure, aggression doesn't help in all facets of a game, but I would guess the benefit outweighs the cost.

The reason I originally brought this up in a previous post was because hfa was present in shooting and rebounding in NBA stats, but not in free throw stats -- this fits well with the concept that aggression helps some areas of a game, but not others.

This saliva-based study seems like it could easily be replicated in other sports -- hope some university has the time to do it.